TWI597376B - Processing device with temperature adjusting device and method for processing substrate - Google Patents

Description

Processing device with temperature adjusting device and method for processing substrate

The present invention relates to a processing apparatus having a substrate holder and a temperature adjustment device, and the temperature adjustment device is configured as a "thermal cavity". The invention further relates to a method of processing a substrate in such a temperature adjustment device.

[definition]

The meaning of "treatment" in the present invention encompasses any chemical, physical, or mechanical effect on the substrate.

The meaning of "substrate" in the present invention is a component, component or workpiece to be disposed of in a processing apparatus. The substrate comprises, but is not limited to, a flat and flat member having a rectangular, square or circular shape. In a preferred embodiment, the present invention is directed to a substantially planar circular substrate, such as a wafer. The material of such a wafer may be glass, semiconductor, ceramic, or any other material that can withstand the above processing temperatures.

"Vacuum treatment" or "vacuum processing system/equipment/chamber" includes at least one outer casing for a substrate to be processed at a pressure below atmospheric pressure and means for processing the substrates.

"Chuck" or "clamp" is suitable for use during processing A substrate holder that fixes a substrate. Such clamping can be achieved in particular by electrostatic forces (electrostatic chuck ESC), mechanical means, vacuum, or a combination of the foregoing. The chuck may contain additional equipment such as temperature control components (cooling, heating) and sensors (substrate alignment, temperature, warpage, etc.).

"CVD" or "Chemical Vapor Deposition" is a chemical process used to deposit a layer on a heated substrate. More than one volatile precursor material is sent to a processing system where volatile precursor materials react and/or decompose on the substrate to produce the desired deposit. A variation of CVD includes low pressure CVD (LPCVD) - a CVD process performed below atmospheric pressure. Ultra High Vacuum CVD (UHVCVD) is typically less than a 10 ^-6 Pa/10 ^-7 Pa CVD process. The plasma method includes microwave plasma assisted CVD (MPCVD) and plasma enhanced CVD (PECVD). These CVD processes use plasma to increase the chemical reaction rate of the precursor.

"Physical Vapor Deposition (PVD)" is a generic term used to describe any of a wide variety of methods for depositing a thin film on a surface of a substrate (e.g., on a semiconductor wafer) by coagulation of a material vaporization pattern. The coating process involves a purely physical process, such as high temperature vacuum evaporation or plasma sputtering bombardment, unlike CVD. Variations of PVD include cathodic arc deposition, electron beam physical vapor deposition, evaporative deposition, and sputter deposition (i.e., glow plasma discharges that are often confined to magnetic tunnels on the surface of the target material).

Terms such as "layer", "coating", "sediment", and "film" are used interchangeably in the present disclosure to deposit thin films in vacuum processing equipment, whether CVD, LPCVD, plasma enhanced CVD ( PECVD), or PVD (physical vapor deposition).

Chuck devices have been widely known that by means of a chuck device, during processing in a vacuum processing chamber, the substrate is positioned and held and temperature adjusted during this process. This adjustment should be understood to include heating the substrate to the desired temperature, maintaining the substrate at the desired temperature, and cooling the substrate to maintain the desired processing temperature, for example, when the process itself tends to overheat a substrate.

In the prior art, the substrate is typically held on the chuck by electrostatic force, by gravity alone, by a weight buckle positioned around the substrate to be processed, or by a clamp or clip that secures the substrate. On the device.

The chuck device often includes a rigid base or support for placing the substrate thereon; the support is heated by a resistive heater or luminaire (for example, a halogen lamp). In many prior art applications of temperature adjustment devices, heat transfer is accomplished by direct contact between the support and the substrate. However, the quality of heat transfer greatly depends on how well the contact can be built. If the substrate is not perfectly planar or one of the substrate and the support is warped during heating, the contact will not be completely surface contact. Therefore, the mixing of heat conduction and radiation will be responsible for heat transfer, which may result in uneven heat distribution on the substrate. Also, thermally induced mechanical stress may damage the substrate. This problem has been solved in two ways: first, by using mechanical means to force the support and the substrate to have closer contact (heat conduction). However, this may enhance the stress on the substrate, which may result in cracking of the substrate, especially thin and/or fragile substrates. The second way is to use the back gas contact. In this case, the gas will be introduced into the base. Heat transfer between the plate support and the substrate by mixing of convection and conduction. However, heat transfer through gas contact is not very effective, especially at the high temperatures to be achieved. Heat loss occurs as the gas leaks out, which limits the choice of gas, except that the gas should not negatively interfere with the process itself. Another problem occurs if the substrate to be processed must be treated on the entire surface exposed to the processing means. In this case, any clamping is impossible. Electrostatic chucks are often used in these situations and are safe and securely clamped. However, the electrostatic effect is extremely temperature dependent and inefficient, especially at very high temperatures (ie, >500 ° C). In addition, any electronic device needed to control power needs to be cooled.

The use of a resistive wire or a halogen lamp to heat the substrate creates another disadvantage. These are all substantially linear or point-like heat sources; in order to properly distribute the heat on the surface, metal blocks are typically used to dissipate heat. However, this adds thermal inertia and additional losses to the overall thermal adjustment device. Alternatively, it is foreseen that there will be a rotating substrate support that rotates relative to the (equal) heat source. However, this increases the mechanical complexity of the overall construction and forces the substrate to be clamped.

Accordingly, it is an object of the present invention to provide a thermal adjustment device that is simple in construction, allows for a non-clamping treatment of the substrate, does not require substrate rotation, possesses low thermal inertia, and achieves at least 500 ° C to 1200 ° C, preferably 750 ° C to 1000 °C, the substrate temperature.

It is an object of the present invention to provide a processing apparatus having a temperature adjustment device disposed in a vacuum processing chamber that allows a large amount of The same substrate processing, whereby the overall structure of the temperature adjustment device is additionally simplified as is known and illustrated as in Fig. 1.

This object is achieved by a processing apparatus and a temperature adjustment apparatus disposed in a vacuum wafer processing chamber, which in sequence comprises: a substrate 19 having an extended and substantially planar surface, a substantially planar heating The element 15 is disposed above the substrate 19 in a plane parallel and away from the surface facing the substrate 19, and a substrate support 14 is configured to carry a substrate 17 around the surface of the substrate 17 One surface faces the heating element directly during operation, wherein a heat reflective surface or mirror 18 is disposed on the surface of the substrate 19; and ̇ there is no additional clamping to hold the substrate in place during operation means.

In a preferred embodiment, the processing device further includes a source of processing material disposed in another plane parallel to the substrate and the heating element and facing directly toward the substrate during operation.

The source of processing material can be any PVD, CVD, or active gas source (for example, for cleaning, post treatment, surface modification, or etching).

A method of disposing a substrate in a processing apparatus as described above includes: 放置 placing a substrate on a substrate support of a respective processing device, The substrate is heated to the desired extent and the substrate is processed in the manner described above.

10‧‧‧Substrate processing unit

11‧‧‧ Target

12‧‧‧ Processing space

13‧‧‧Baffle

14‧‧‧Substrate support

15‧‧‧heating elements

15'‧‧‧ heating element

16‧‧‧ pillar

16’‧‧‧ pillar

17‧‧‧Substrate

18‧‧‧Mirror

19‧‧‧Base

20‧‧‧ channel

Figure 1 is a cross-sectional view of a processing apparatus in accordance with the present invention.

Figure 2 shows a possible design of a heating element according to the invention.

Alignment (top view) of the base substrate and the heating element shown in Fig. 3.

A substrate processing apparatus 10 having a temperature adjustment device includes a substrate 19 to be disposed in a vacuum processing chamber. The chamber or housing has been omitted in Figure 1 and will be designed as known in the art, including the necessary means to create a vacuum, remove exhaust gases, wires, and loading/unloading facilities for the substrate. . A heating element 15 is disposed on the substrate 19, preferably disposed parallel to the surface of the substrate 19 on the column(s) 16 to provide a gap between the substrate 19 and the heating element 15. The heating element can be substantially selected from prior art heating elements, such as resistive heaters, radiant heaters, or particularly preferred carbon-based heater devices. A substrate 17 is disposed in a plane parallel to the substrate 19 and the heating element 15, preferably between 5 mm and 20 mm. The substrate 17 is preferably held by a substrate support 14, which is designed as an annular load-bearing area or as a selective support at the circumference of the substrate.

In the context of the present invention, it is important to note that active clamping, weight rings, or clamps are not required. The substrate is placed on the substrate support 14 and held by its own weight. So won't be The fixing means applies mechanical stress. A target 11 is placed in another plane parallel to the aforementioned substrate, heating element, and substrate. The target to substrate distance TSD is selected to be between 4 and 10 cm, preferably between 5 and 8 cm. There is a processing space 12 between the substrate 17 and the target 11. This processing space will have plasma during sputtering. A working gas (reaction gas or inert gas) can be injected from the side near the edge of the target. PVD sputtering processes are known in the art and are therefore not described in detail herein. The material is spattered from the target 11 by the plasma and deposited on the substrate 17. It is foreseeable that a baffle 13 is provided to protect the substrate support 14 from being covered by the target material. This flap 13 can be easily replaced in the maintenance section. As shown in Fig. 1, the baffles are constructed such that a layer deposited on the substrate 17 covers the entire surface of the target 11.

The heating element 15, preferably a carbon heater, is a radiant heating element. In an embodiment of the invention, the carbon heating element is coupled to a power source capable of delivering 3 Kw of electrical power. The carbon element will heat to 2300 ° C and allow substrate temperatures above 750 ° C (in the case of sapphire or tantalum substrates). In order to achieve effective thermal management, a mirror or reflection means 18, preferably having good reflection characteristics in the infrared portion of the spectrum, is disposed directly on the substrate 19, facing the heating element 15 (on the side facing away from the substrate 17, as described 1 shown in the figure). It has been shown that even a substrate (glass, germanium, sapphire) having a low absorption characteristic in the infrared portion of the spectrum can be "sandwiched" by a substrate 17 and a heating element 15 on two reflective surfaces (for example, mirror 18 and Between the targets 11) is effectively heated. This "thermal cavity" is very effective because radiation from the heating element 15 is directed and redirected from the front side facing the substrate 17 and its back side. The The radiation will substantially sink and reflect between the two reflective surfaces until absorbed (or lost) by the substrate.

The substrate 19 is preferably cooled by fluid in the channel 20 foreseen in the metal block. Preferably, the mirror 18 and the substrate support 14 thus use the substrate 19 as a heat sink.

The heat mirror 18 can be made of a nickel coating or a replaceable thin nickel plate that is placed on the substrate 19. Other highly reflective materials that have good reflectivity, especially good reflectivity in the infrared portion of the spectrum, can also be used.

The corresponding portion or second mirror of the cavity is the target 11. Substantially the same reflective requirements apply to the mirror 18; however, of course, the layer to be deposited determines the choice of material. Examples of materials that can be used are Al, Ti, Ag, Ta, and alloys thereof.

Due to the efficiency of the heating element 15, the substrate support 14 must be made of a material that is resistant to high temperatures. Titanium is the material of choice or high strength steel can be used.

The substrate processing apparatus 10 of the present invention does not limit the sputtering target 11 used in PVD applications. It can be used in CVD or PECVD applications where a showerhead or another overhead processing gas inlet is provided to replace the target 11. It should be understood that the sprinkler head and gas inlet must meet the a.m. limit and "hot chamber" quality requirements in an equivalent manner. Materials such as polished steel, Ni, and Al can be used.

A plan view of one of the embodiments of the heating element 15' shown in Fig. 2. The column 16' is identical to the column 16 in Figure 1. This embodiment includes a double helix and the electrical connector is on the outside. Heating element It will be cut from a carbon fiber board or pressed into individual modules. Carbon or carbon fiber composites are known per se and are commercially available. The shape of the heating element (the width and thickness of the coil) is optimized to achieve a uniform heating effect. A thickness of 2.5 mm has been chosen in an embodiment which is a compromise of weight, material stability, and total electrical resistance. In the cross-sectional view, the rectangular shape of the individual coils is superior to a square or circular shape.

The final structure is self-supporting, dependent on the diameter and thickness of the heating element. If a bend occurs during operation, the structure is stabilized by the ceramic seat.

The base substrate 17 shown in Fig. 3 is aligned with respect to the heating element 15. It is preferred to provide the electrical connection outside of the effectively heated substrate region because the connector does not have the same operating temperature as the heating element itself. Therefore, temperature non-uniformity can be avoided, especially in the edge region of the substrate. As a result, the size of the heating element is substantially the size of the substrate plus the extension of the connectors.

The thermal adjustment device is of course also applicable to the non-reflective target 11 and/or the highly absorptive substrate 17. For example, a SiC substrate does not require a thermal cavity with two reflective surfaces. However, placing the mirror 18 behind the heating element will still increase the heating efficiency in this case.

The invention described above can be used for circular, rectangular, or square substrates of different sizes. Preferably, it can be used in substrate processing systems designed to process 4 inch, 6 inch, 8 inch (200 mm), or 12 inch (300 mm) wafer diameters. Due to the nature of its heating elements, it is easy to construct a medium size.

The temperature adjustment device as described is heated by its direct radiation The principle relationship has a low thermal inertia. The advantage is that the substrate can be heated in a stepwise manner by changing the electric power quickly or in a stepwise manner. The same advantages apply to cooling and cooling.

10‧‧‧Substrate processing unit

11‧‧‧ Target

12‧‧‧ Processing space

13‧‧‧Baffle

14‧‧‧Substrate support

15‧‧‧heating elements

16‧‧‧ pillar

17‧‧‧Substrate

18‧‧‧Mirror

19‧‧‧Base

20‧‧‧ channel

Claims (16)

A substrate processing apparatus having a temperature adjustment device, the temperature adjustment apparatus comprising: a first substrate (19) having an extended and substantially planar surface, and a substantially planar heating element (15) disposed in the In a plane above the substrate (19), the plane is parallel and away from and facing the surface of the substrate (19), a substrate support (14) configured to carry the substrate around a substrate (17) (17) The substrate (17) has a surface and another surface opposite the one surface such that the one surface of the substrate (17) is separated from the heating element during operation and directly faces the heating element (15) The temperature adjusting device further includes: a first heat reflecting surface (18) disposed on the surface of the substrate (19); a second heat reflecting surface along the other of the substrate (17) The surface is disposed and directly faces the other surface of the substrate (17); and wherein the substrate (19) comprises a cooling device. The substrate processing apparatus of claim 1, wherein the first heat reflecting surface (18) comprises a nickel coating or a nickel flat plate disposed on the substrate (19). The substrate processing apparatus according to claim 1, wherein the second reflective surface is a source of a treatment material or a target (11) of the physical vapor deposition source. According to the substrate processing apparatus of claim 1, wherein the The second reflective surface is a showerhead or process gas inlet for a CVD or PECVD source. The substrate processing apparatus according to claim 1, wherein the material of the second reflective surface comprises Al, Ti, Ag, Ta, an alloy thereof, and Ni. The substrate processing apparatus according to claim 1, wherein a distance between a plane of the heating element (15) and a plane in which the substrate (17) is disposed during operation is between 5 and 20 mm. A substrate processing apparatus according to claim 1, wherein the substrate support (14) is designed as an annular load-bearing area or as a selective support on the circumference of the substrate. The substrate processing apparatus according to claim 1, wherein the target-substrate distance TSD between the plane of the substrate (17) during operation and the second reflective surface or target (11) is selected to range from 4 Up to 10cm. A substrate processing apparatus according to claim 8 wherein the TSD is between 5 and 8 cm. A substrate processing apparatus according to claim 1, wherein a baffle (13) is disposed between the second reflective surface or the target (11) and the substrate support (14), the baffle (13) It is configured to protect the substrate support (14) from being covered by the disposal material when a layer deposited on the substrate (17) covers the entire surface facing the target (11). The substrate processing apparatus according to claim 1, wherein the heating element (15) is a resistance heater. The substrate processing apparatus according to claim 1, wherein the heating element (15) is a radiant heater. The substrate processing apparatus according to claim 1, wherein the heating element (15) is a carbon heater. The substrate processing apparatus according to claim 13, wherein the carbon heater has a double helix structure and the electrical connector is on the outer side. The substrate processing apparatus according to claim 14, wherein the electrical connectors are disposed outside the substrate region that is effectively heated. A method for processing a substrate in a processing apparatus, comprising: placing a substrate (17) on a substrate support (14) of a substrate processing apparatus according to claim 1; heating the substrate to a preset temperature; And disposing the substrate.